Abstract:

【Objective】 In experiments, the heterosis QTL for yield traits was detected and the genetic basis of heterosis in rice was studied by method of QTL mapping. 【Method】 A backcross (BC1) population derived from XQZB/RILs was developed to observe the heterosis of six yield traits in two location trials. QTLs for six yield traits were determined using Windows QTL Cartographer 2.5 with composite interval mapping. 【Result】 Heterosis of majority yield traits were stronger. As the results indicated, a total of 20 significant heterosis QTLs for six yield traits were detected distributing on rice chromosomes 2, 3, 6, 7, 8, and 10, including three heterosis QTLs for grain yield (GYD) per plant, two heterosis QTLs for number of panicle (NP) per plant, six heterosis QTLs for total number of spikelet per panicle (TNSP), four heterosis QTLs for number of filled grain per panicle (NFGP), four heterosis QTLs for spikelet fertility (SF) and one heterosis QTL for 1000-grain weight (TGWT), respectively. The phenotypic variance explained by a single heterosis QTL ranged from 4.90% to 12.85%. 【Conclusion】 A total of 20 significant heterosis QTLs for six yield traits were detected and five heterosis QTLs among them were stable expression in two trials, included qHNP-3, qHTNSP-7, qHNFGPH-7, qHSF-7, qHTGWT-3. In the checked 20 heterosis QTLs, 13 of them were also checked in the RIL population, the degree of overlap were bigger up to 65%. It is suggested that additive effects also play an important role for yield heterosis.

Key words: rice (Oryza sativa L.)')">rice (Oryza sativa L.), yield traits, heterosis, quantitative trait locus (QTL), backcross population (BC1)